In this page, we will introduce 15 best GTK3 themes that you can use with Ubuntu 12.04 (Precise Pangolin) under Unity or Gnome Shell. The themes are also compatible with other Ubuntu versions (12.10/11.10, Linux Mint 13, etc.). To make the installation of these themes easier, I have uploaded them all to our custom PPA. You can add our PPA with these commands:sudo add-apt-repository ppa:upubuntu-com/gtk3sudo apt-get update

To enable these themes, you can use GNOME TWEAK TOOL, MyUnity, or use simply the commands provided with each theme given below. Gnome Tweak Too can be installed with this command: